LIVER SWE and SONOGRAPHER EFECT

 

Concerning our study results, when controlling for all factors (machines, probes, and liver volunteers in time), 17% of inter-observer variability was due to sonographers. 

The differences in scanning procedures reported by healthy liver volunteers may explain why SWE values varied among sonographers, but the reason these scan ning procedures varied among sonographers in the first place is not clear. When sonographers were debriefed after the study, all reported receiving training from the manufacturer. However, there are nuances to the protocol that are likely not included in the training or the consen sus guidelines. For example, some sonographers retain the first 10 SWE values they capture while others care fully review and select their SWE values, retaining some and resampling others. Some sonographers tend to keep the lowest measurements, or the measurements with the least variability. Another area of potential variability is where the ROI is placed within the color box. It is pos sible that these differences in sampling produced a selec tion bias that led to differences in SWE values for some liver volunteers but not others (i.e., poor sampling may be less sensitive to the day-to-day differences within liver volunteers; or contrariwise, better sampling may be more robust to day-to-day differences occurring in liver volun teers). That is, it is possible that by following strict pro tocols, along with multiple resamples throughout a day, a more reliable measure of a person’s SWE may be ob tained. Likewise, less strict adherence to protocols, taken only once, may hide true differences in SWE values and thus appear more reliable than they are.

Conclusion 

 In conclusion, liver shear wave elastography (SWE) values are a function, to some degree, of the sonogra phers obtaining these values. Caution should be used in interpreting SWE values, particularly when relying on strict thresholds for clinical decision making.